Nontuberculous mycobacterial blood stream and cardiac infections in patients without HIV infection

Nontuberculous Mycobacterial Infective Endocarditis: A Systematic Review of Clinical Characteristics and Outcomes

Background

Infective endocarditis (IE) due to nontuberculous mycobacteria (NTM) is a rare infection, and several outbreaks have been reported in the last 2 decades. However, the clinical spectrum is still poorly understood. This systematic review aimed to evaluate the clinical characteristics and outcomes in NTM IE.

Methods

We searched the major electronic databases (PubMed, Scopus, and Google Scholar) with appropriate keywords to December 2023. We included studies based on predefined diagnostic criteria, and relevant data were collected on clinical presentation and treatment outcomes. The study was registered with PROSPERO (CRD42023492577).

Results

A total of 97 studies were reviewed, encompassing 167 patients with NTM IE. The earliest cases were reported in 1975, involving M chelonae and M fortuitum. M chimaera was the most prevalent species (38.9%), though rapidly growing NTM (RGM) were more common than slow-growing NTM (SGM; 59.3% vs 40.7%). Disseminated NTM infection occurred in 84% of cases, with bone marrow infiltration and osteomyelitis as frequent manifestations. Prosthetic valves were the main risk factor, present in 63.5% of cases. In native valve IE, nearly all cases (n = 27, 96%) were attributed to RGM. The overall mortality rate was 44.9%, with conservative management without surgery associated with poorer outcomes (66.7% vs 30.6%). Mortality was comparable between SGM and RGM IE, although relapses were more common in SGM IE (17.6% vs 1.9%).

Conclusions

This review highlights the changing epidemiology of NTM IE with the emergence of RGM IE. Disseminated infections in the setting of prosthetic valves warrant NTM evaluation. The high mortality rate necessitates the role of early surgery.

Native valve endocarditis and pacemaker infection with Mycobacterium fortuitum

Endocarditis and cardiac device infection due to Mycobacterium fortuitum is a rare entity in the hospital settings. We report a case of pacemaker infection and native valve endocarditis due to Mycobacterium fortuitum, which was associated with tricuspid valve vegetation. two days after admission with fever, chills, body aches and swelling around her pacemaker, the patient’s pacing system was surgically removed. The patient was then discharged at day 16 after surgery and treated with a multidrug regimen of azithromycin, levofloxacin, imipenem/cilastatin, and amikacin for six weeks followed by trimethoprim/sulfamethoxazole plus doxycycline for a further three months.

Cardiac resynchronization therapy-defibrillator pocket infection caused by Mycobacterium fortuitum: a case report and review of the literature

BACKGROUND

With the rising utilization of cardiovascular implantable electronic devices (CIEDs), infections secondary to device implantation are increasingly encountered. Staphylococcus aureus and coagulase-negative staphylococci are usually the predominant causative organisms. A CIED infection due to non-tuberculous mycobacteria (NTM) is extremely rare.

CASE PRESENTATION

A 68-year-old man was admitted to our hospital with a history of pain and swelling at his cardiac resynchronization therapy-defibrillator (CRT-D) pocket site, for 4 days. The CRT-D had been implanted 2 weeks prior. The exudate smear was positive for acid-fast bacilli and culture results revealed rapidly growing nontuberculous mycobacteria (RGM). After an urgent removal of the device followed by 1 year of antibiotic treatment, the patient was completely cured. A new device was finally implanted, 3 years later.

CONCLUSIONS

Infections caused by nontuberculous mycobacteria following the implantation of cardiac devices are very rare. The typical manifestations of post-implantation CIED infections caused by RGMs include an early onset, with local redness, swelling, and spontaneous drainage. Systemic symptoms such as fever, chills, and fatigue are absent. Mycobacterium fortuitum is the most common species of RGM implicated in CIED infections, the manifestations of which usually appear within several weeks of the implantation procedure. An urgent removal of the device and appropriate antibiotic therapy are essential therapeutic measures. This is the first such reported case, in which the patient has been re-implanted with another device at the same site, after achieving a complete cure. We followed-up the patient for an additional 3 years and observed that the patient remained free of infection. Our case report shows that though an RGM infection is rare and difficult to treat, it can be completely cured. In addition, we demonstrated that it is subsequently possible to safely re-implant a CIED for the patient, at the same site.

Nontuberculous Mycobacteria in Children: A Focus on Bloodstream Infections

BACKGROUND

Nontuberculous mycobacteria (NTM) are ubiquitous organisms with variable disease-causing potential. Bloodstream infections caused by NTM in children are poorly described.

METHODS

We describe a retrospective case series of children with culture-confirmed mycobacterial disease managed at the Children's Hospital at Westmead between July 2005 and June 2015.

RESULTS

Sixty-five patients had 149 positive NTM cultures; 55 (83.0%) episodes in 54 patients were considered clinically significant. Of the 54 children who met criteria for NTM disease, 25 (46.3%) had lymphadenitis, 13 (24.1%) lung disease, 8 (14.8%) had soft tissue infection or osteomyelitis and 8 (14.8%) had bacteremia. All children with bacteremia had a central venous catheter; those with pulmonary infection had underlying lung disease and all children with soft tissue infection or osteomyelitis had a history of recent penetrating injury. Disease caused by Mycobacterium avium-intracellulare complex was most common, accounting for 19 (76.0%) and 7 (53.8%) lymph node and lung infections, respectively. The most frequently isolated rapid growing mycobacteria were Mycobacterium fortuitum (8; 15%) and Mycobacterium abscessus (6; 11%), with M. fortuitum accounting for the majority (6; 75%) of bloodstream infections. Six (75%) patients with bacteremia had their intravenous catheter removed and all had a favorable outcome. A single disease relapse was reported in 1 of 2 patients with a retained catheter.

CONCLUSION

Lymphadenitis was the most common NTM disease manifestation and not associated with comorbidity. NTM bacteremia was always associated with a central line and catheter removal with cure. We were unable to assess the added value of various antibiotic regimens.

Airway delivery of interferon-γ overexpressing macrophages confers resistance to Mycobacterium avium infection in SCID mice

Mycobacterium avium (M. avium) causes significant pulmonary infection, especially in immunocompromised hosts. Alveolar macrophages (AMs) represent the first line of host defense against infection in the lung. Interferon gamma (IFN‐γ) activation of AMs enhances in vitro killing of pathogens such as M. avium. We hypothesized that airway delivery of AMs into the lungs of immunodeficient mice infected with M. avium will inhibit M. avium growth in the lung and that this macrophage function is in part IFN‐γ dependent. In this study, normal BALB/c and BALB/c SCID mice received M. avium intratracheally while on mechanical ventilation. After 30 days, M. avium numbers increased in a concentration‐dependent manner in SCID mice compared with normal BALB/c mice. Airway delivery of IFN‐γ‐activated BALB/c AMs or J774A.1 macrophages overexpressing IFN‐γ into the lungs of SCID mice resulted in a significant decrease in M. avium growth (P < 0.01, both comparisons) and limited dissemination to other organs. In addition, airway delivery of IFN‐γ activated AMs and macrophages overexpressing IFN‐γ increased the levels of IFN‐γ and TNF‐α in SCID mice. A similar protective effect against M. avium infection using J774A.1 macrophages overexpressing IFN‐γ was observed in IFN‐γ knockout mice. These data suggest that administration of IFN‐γ activated AMs or macrophages overexpressing IFN‐γ may partially restore local alveolar host defense against infections like M. avium, even in the presence of ongoing systemic immunosuppression.

Patient Report and Review of Rapidly Growing Mycobacterial Infection after Cardiac Device Implantation

As more of these devices are implanted, such infections are likely to be more frequently reported.

Mycobacterial infections resulting from cardiac implantable electronic devices are rare, but as more devices are implanted, these organisms are increasingly emerging as causes of early-onset infections. We report a patient with an implantable cardioverter-defibrillator pocket and associated bloodstream infection caused by an organism of the Mycobacterium fortuitum group, and we review the literature regarding mycobacterial infections resulting from cardiac device implantations. Thirty-two such infections have been previously described; most (70%) were caused by rapidly growing species, of which M. fortuitum group species were predominant. When managing such infections, clinicians should consider the potential need for extended incubation of routine cultures or dedicated mycobacterial cultures for accurate diagnosis; combination antimicrobial drug therapy, even for isolates that appear to be macrolide susceptible, because of the potential for inducible resistance to this drug class; and the arrhythmogenicity of the antimicrobial drugs traditionally recommended for infections caused by these organisms.

Mycobacterial endocarditis: a comprehensive review

OBJECTIVE

A systematic analysis was made in view of the epidemiology, clinical features, diagnosis, treatment and main outcomes of mycobacterial endocarditis.

METHODS

The data source of the present study was based on a comprehensive literature search in MEDLINE, Highwire Press and Google search engine for publications on mycobacterial endocarditis published between 2000 and 2013.

RESULTS

The rapidly growing mycobacteria become the predominant pathogens with Mycobacterium chelonae being the most common. This condition has changed significantly in terms of epidemiology since the 21st century, with more broad patient age range, longer latency, prevailed mitral valve infections and better prognosis.

CONCLUSION

Mycobacterial endocarditis is rare and the causative pathogens are predominantly the rapidly growing mycobacteria. Amikacin, ciprofloxacin and clarithromycin are the most frequently used targeted antimicrobial agents but often show poor responses. Patients with deep infections may warrant a surgical operation or line withdrawal. With periodic multidrug therapy guided by drug susceptibility testing, and surgical managements, patients may achieve good therapeutic results.

Brown-Pigmented Mycobacterium mageritense as a Cause of Prosthetic Valve Endocarditis and Bloodstream Infection

Mycobacterium spp. are a rare cause of endocarditis. Herein, we describe a case of Mycobacterium mageritense prosthetic valve endocarditis. This organism produced an unusual brown pigment on solid media. Cultures of valve tissue for acid-fast bacilli might be considered in some cases of apparently culture-negative prosthetic valve endocarditis.

Mycobacterium neoaurum causing prosthetic valve endocarditis: a case report and review of the literature

Mycobacterium neoaurum is a rare cause of bacteremia, and infection usually occurs in an immunocompromised host in the setting of an indwelling catheter. Prosthetic valve endocarditis due to non-tuberculous mycobacteria typically carries a dismal prognosis; we report a case of M. neoaurum prosthetic valve endocarditis with favorable response to antimicrobial therapy without surgical intervention.

Spontaneous endocarditis caused by rapidly growing non-tuberculous Mycobacterium chelonae in an immunocompetent patient with rheumatic heart disease

We are reporting the first case of spontaneous endocarditis caused by rapid grower non-tuberculous Mycobacterium chelonae in a case of rheumatic heart disease. The diagnosis was confirmed as there was repeated isolation of rapidly growing atypical Mycobacterium from blood culture which was identified as M. chelonae by Reverse line probe assay. The patient presented with pyrexia of unknown origin. Later she was found to have rheumatic heart disease with severe aortic regurgitation & large vegetation was seen attached to the aortic valve. She was treated with rifampicin, clarithromycin, amikacin & levofloxacin based on culture & sensitivity. She succumbed to her illness after development of large cerebral infarction due to embolization of vegetation from aortic valve.